Liquid electrophotographic (LEP) printing uses a liquid ink for printing on substrates rather than using a dry, powder toner. Common examples of LEP printing machines are the HP® digital Indigo™ printing presses. The toner particles in the liquid ink used in LEP printing are sufficiently small such that the LEP-printed images do not mask the underlying surface roughness/gloss of, for example, paper substrates. The liquid ink (also referred to herein as “ink”, “liquid toner”, or “LEP ink”) used in LEP printing is a suspension of small pigment particles in the range of about 1 to 2 microns in a nonaqueous liquid. HP® ElectroInk® is a commonly used liquid ink for liquid electrophotographic printing. LEP printing is considered to give some of the best digital print quality images at a relatively rapid speed.
However, it has been found that LEP printed images will not adhere to substrates as well as images printed using electroreprographic printing methods that utilize a dry-toner process. While conventional compositions have been applied to substrates to attempt to improve adhesion of the image formed from liquid toner, further improvements are necessary due to (1) inconsistencies in adhesion performance depending on the grade of paper utilized as the substrate and (2) the difficulty in obtaining a near perfect (100%) adhesion of images printed from LEP printing as tested by HP® standard procedures, regardless of the grade of paper.
Accordingly, it is desirable to provide systems and methods for treating a substrate and for improving adhesion of an image to a treated substrate. Furthermore, other desirable features and characteristics will become apparent from the subsequent summary and detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.